This invention relates to pipe connections for cooling headers, and more specifically, to connections between a coolant header and a liquid cooled thyristor stack or other electrical component which dissipates large amounts of heat.
Cold plates, or heat sinks are typically clamped between the thyristors of a thyristor stack and are cooled by liquid, e.g., deionized water, circulating through the plates, carrying heat away from the thyristors. The cold plates or heat sinks are connected to coolant headers by a plurality of flexible hoses and associated hose couplings or connectors. Over extended periods of time, the reliability, maintainability and survivability of flexible hoses in such an environment have not proven completely satisfactory. An example of a thyristor stack connected to coolant apparatus by means of flexible hoses is shown in U.S. Pat. No. 4,513,346.
It is also known to connect heat sinks clamped between a plurality of disk thyristors to a coolant header by means of a plurality of heat pipes, each of which is provided with flexible bellows-type connectors at either end. An arrangement of this type is disclosed in U.S. Pat. No. 4,023,616.
It is an object of this invention to minimize the number of flexible hoses and associated connections needed to establish communication between the cold plates, or heat sinks, of a thyristor stack and a nearby coolant manifold or header.
In one exemplary embodiment of the invention, ports of the cold plates or heat sinks of a disk-type thyristor stack (incorporated into, for example, a cyclo-converter) are provided as integral substantially rigid tubular members which extend away from the cold plate and are connected directly to an associated coolant manifold or header. The free ends of the relatively rigid tubular members each have a reduced diameter portion for receiving an electrically non-conductive insulating bushing, having a cylindrical forward body portion and a rearward radial flange. The insulating bushing may be telescoped over the reduced diameter portion of the tubular member so that the radial flange abuts against a radial shoulder formed in the wall of the tubular member.
The insulating bushing is designed for reception within an appropriate opening, or inlet, in the coolant manifold, the opening provided with a plurality of axially spaced O-rings for providing a fluid seal between the insulating bushing and the manifold. The O-rings also allow relative movement between the tubular member and the manifold during shock conditions, but restrain any significant and undesirable movement of the tubular member via the bushing in both an axial and lateral directions.
It will be appreciated that the above described arrangement permits the elimination of the conventional cold plate-to-coolant manifold hoses, while at the same time, permitting quick connection and disconnection of the thyristor stack from the coolant manifold.
Another advantage of the invention is that it can be used with relatively thick walled, flat plate-type coolant manifolds where the inlets are drilled through the relatively thick plate, or in tubular coolant manifolds where the inlets are in the form of welded nipples projecting from the manifold. In either case, the axially spaced O-rings are provided to seal against the insulating bushing.
A further advantage of this invention is that parallel cooling of each of the cold plates is facilitated. In the past, the thyristor cold plates has been arranged typically in a series cooling loop, apparently in order to reduce cooling hose complexity. Since the utilization of coolant hoses have been eliminated with the present invention, a more efficient parallel cooling arrangement is easily implemented, if desired.
It will be understood by those of ordinary skill in the art that the connector construction in accordance with this invention is not limited to use with cold plates of thyristor stacks, but may be utilized in conjunction with other components as well.
Additional objects and advantages of the present invention will become apparent from the detailed description which follows.